Free space is an extremely valuable resource within a multiple camera endoscope tip section. Such tip sections typically include a plurality of cameras, a plurality of optical systems, a plurality of illuminators, a flexible electronic circuit board configured to support and encapsulate the components and a working channel configured for the injection of fluids and for the insertion of miniscule surgery tools.
An optical system for a tip section of a multiple sensor endoscope comprising a front-pointing camera sensor, a front objective lens system, a side-pointing camera-sensor, and a side objective lens system is disclosed in U.S. patent application Ser. No. 13/882,004, entitled “Optical Systems for Multi-Sensor Endoscopes” and filed on May 23, 2013, which is herein incorporated by reference in its entirety.
A flexible electronic circuit board for a multiple camera endoscope tip section is disclosed in Patent Cooperation Treaty Application Number PCT/IL2011/050049, entitled “Flexible Electronic Circuit Board for a Multi-Camera Endoscope” and filed on Dec. 8, 2011, which is herein incorporated by reference in its entirety. The circuit board comprises: a front camera surface configured to carry a forward looking camera; a first side camera surface configured to carry a first side looking camera; a second side camera surface configured to carry a second side looking camera; one or more front illuminator surfaces configured to carry one or more front illuminators; and, one or more side illuminators surfaces configured to carry one or more side illuminators.
The flexible circuit board is connected to the central control unit via a multi-wire cable. The multi-wire cable is welded on the board in a designated location, freeing additional space within the tip section assembly and adding flexibility to the cable access.
A multiple sensor or multiple viewing elements endoscope tip section comprising a front-pointing camera and two or more side-pointing cameras positioned at or in proximity to a distal end of the tip section and a working channel configured for insertion of a surgical tool is disclosed in U.S. patent application Ser. No. 13/655,120, entitled “Multi-Camera Endoscope” and filed on Oct. 18, 2012, which is herein incorporated by reference in its entirety, and assigned to the Applicant of the present specification. As described in the '120 application, the field of view (FOV) of each camera sensor in a multiple sensor endoscope is illuminated by two or more illuminators that are light emitting diodes (LEDs). Thus, multiple sensor endoscopes' tips that include a right pointing camera or viewing element, a front pointing camera or viewing element and a left pointing camera or viewing element may include a minimum of 9 or more LEDs. Since the FOVs' depth in different orientations, for example in a patient's colon, can vary significantly during a colonoscopy procedure, illuminating all LEDs with a fixed illumination intensity is sub-optimal, may be too weak in some orientations for example and may drive the camera sensor arrays beyond their dazzle limits due to light reflection from a nearby wall in other orientations.
One approach for controlling the illumination of a multiple illuminator endoscope system may be provided by dynamically controlling the emitted light intensities. However, since multiple illuminator endoscope systems may include 10 or more illuminators, controlling the light intensity of each illuminator independent of the other illuminators dynamically may be a difficult task.
Multiple-camera/viewing element endoscope digital image processing is a computationally demanding task. Typically, each image sensor within each viewing element captures 50 to 60 frames per second (progressive scanning) or 50 to 60 fields per second (interlaced scanning). Each frame includes, within a high definition (HD) video mode, 1920×1080 pixels, summing up to more than 2 million pixels per frame where each RGB (red, green, blue) pixel is encoded by 3 data bytes. A multiple camera endoscope comprising a front pointing camera and two side pointing cameras typically generates about 75,000 video packets per frame, with a 60 frames per second rate, which sums up to approximately 1 Gigabyte (GB) per second.
Signal processors that can manage such high data rates are too large to be placed within a multiple camera endoscope tip section. Thus, multiple camera endoscopes need to process and transfer the video packet data stream of approximately 1 GB/second through the endoscope body via wires connected to an external display.
Since free space is such a valuable resource, the number of control and power lines used for data transfer from the endoscope tip section and for the endoscope tip's illuminating system, through the endoscope elongated body, and to a central control unit, should be minimized.
Therefore, it would be highly advantageous to provide “daisy-chained” multiple camera endoscope systems configured to transmit video data over a single serial line, which can optimize overall system performance.
While daisy-chained, serially connected illuminators of multiple camera endoscope systems can provide optimized overall system performance in one system configuration, some drawbacks may include:                1. Identical current flow through serially connected LEDs that is dictated by the current flow of the LED that illuminates with the most power at a particular moment. Thus, power may be wasted, which may heat the endoscope's tip section, and furthermore, may over-expose the sensors' arrays in excessively illuminated regions.        2. The supply voltage in a daisy chain of serially connected LEDs is proportional to the number of chained LEDs. Therefore, the number of LEDs that may be chained in endoscope's tip section is limited for at least safety reasons. Having a multiple number of control and power lines for each LED connected in parallel to a controller may solve these concerns, but it may waste a valuable volume at the endoscope's tip section.        
As such, it would also be highly advantageous to provide parallel illuminating systems that require a minimal number of control and power lines and allow for regulation of each illuminator's illumination intensity independently.